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G40 conversion - no spark/fuel

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Hi guys. I'm reasonably new on here - been on club G40 for a good few years tho. Basically I've reshelled my G40 into a breadvan, engine has been fully rebuilt etc.

 

My issue is no spark and the injectors aren't firing. I have fuel pressure at the rail, which as far as I can see means that both the ecu relay and the fuel pump relay are good. I've got 12v at the coil with the ignition on, and I've checked the resistances and theyre all good too (this was a brand new coil 6 years ago and has done ~200 miles). The distributer again was a brand new part just before my G40 died 6 years ago, but I know Hall senders can cause issues so I swapped it out for the known working item from the old 1.0 spi engine, and still no luck. All of this seems to be pointing towards an ecu fault but I'm sure there will be something I'm missing. Anyone on here got any ideas? Help is very much appreciated.

 

Cheers

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  • It covers all Digifant I&II cars, as far as I know they all use the same/similar sensors. I can't get a link just now as its blocked on my work PC but if you google "digifant I and II pro training

spi dizzy isnt compatible ...although would run 

 

unbolt the dizzy but leave the wires on ...ign on then turn the dizzy by hand , you should hear the fuel pump prime if the hall sender is working

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Thanks mate will give that a try. the other thing I was thinking was when I had the engine running years ago, I remember the dizzy being hard up on one side of the slots - when ive tried to run it now its been in the middle. Could the coil be trying to fire when the rotor arm isn't in contact with a point on the cap? will try starting it after work with the dizzy in different settings to see if that makes a difference anyway.

shouldnt be right at the end of the slot

 

if you turn the crank with a socket you can line up the timing marks on the crank /cam ...when both are lined up the rotor should point at a notch on the dizzy housing , that would be good enough to start and run then fine tune with a strobe light   

 

 

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I knew it wasn't right but it was the only way I could get it to run before.. I did this for setting it up HT lead positions anyway and all looked good.  

possibly a tooth out on the cam ...line it up and post a photo

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When I built the engine I timed the cam up on the vernier pulley using a clock gauge and crank angle gauge so that side of it is definitely spot on

This won't help you one little bit - but it may be of interest.

The rotor arm NEVER makes contact with the segments in the cap - The spark jumps the gap, which accounts for the crud that builds up on both surfaces.

If the rotor did manage to contact a cap segment, it would most likely shatter the cap.

 

Regards

  • Author

I managed to find a Digifant pro-training manual which lists how to test your loom/ecu and it appears my ecu is knackered :-| Possibly a result of sitting in a damp garage for 6 years, possibly a result of firing it up without the main loom earth terminated properly, I'm not too sure.

 

Anyone got a spare lying about? Could do with one asap

 

Cheers :D

cheeky ask but does your manual cover the 3f /gt polo ...could use some diagrams for that 

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It covers all Digifant I&II cars, as far as I know they all use the same/similar sensors. I can't get a link just now as its blocked on my work PC but if you google "digifant I and II pro training manual" you should be able to find it as a pdf. Its a proper VW manual and covers everything you should need. Serious amount of useful info

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I've also managed to find a Bulgarian autofactors that say they stock G40 ecu's.. Theyre called spectromatic and have a pretty comprehensive stock of old ecu's listed by part numbers

guess youve scanned ebay for it via the part numbers...i usually find something in germany or poland

  • Author

Yeah mate, one on german ebay but its 250EUR.. will give Poland a try as well never thought of it. I've ordered from that Bulgarian place but not holding out too much hope, thought it would be worth a punt at £45 :D

sounds a bit of a bargain 

 

theres some facebook groups to try if youre on there too

  • Author

Aye seems a bit to good to be true but time will tell :D

 

I'm on facebook but not on any polo related pages.. what ones do you recommend?

alot are full of kids talking sh1t but some good amongst it all lol

 

clubpolo , mk2 and mk2 f owners , polo/derby 86c telimarket ...anything polo related really 

  • Author

Seems to be the way with facebook these days haha! will give them a try. Cheers mate :D

  • 5 months later...

I have what sounds like the very same issue with my GT. Earth to the ecu wasn't right and burned out the ecu. I have a spare but that has almost the opposite issue, constant sparks and injectors. Sounded like a time bomb! 🤣 So I'm on the hunt for yet another ecu aswel, I think. 

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